Submitted by Dup1337, also found by SpicyMeatball
https://github.com/code-423n4/2024-06-krystal-defi/blob/f65b381b258290653fa638019a5a134c4ef90ba8/src/V3Automation.sol#L79-L81
https://github.com/code-423n4/2024-06-krystal-defi/blob/f65b381b258290653fa638019a5a134c4ef90ba8/src/StructHash.sol#L274-L296
User signed orders can be replayed
All orders managed by the Krystal team are signed by the user, executed by the operator and the signature is verified on-chain:
However, there is no nonce field in the StructHash.Order. That means that the same hashed order can be reused multiple times. 
Whats also important is that the order is used only to verify if it was signed by the user, however its not checked if the order that user signed is the same as the params passed by the operator, because ExecuteParams sent to V3Automation.execute() use other set of params to indicate the action to perform:
And later in the function, params.userOrder is not used, only the params prepared by the operator:
Actually, this behavior is shown in test/integration/V3Automation.t.sol:
In the test above, emptyUserConfig - being really empty, i.e. consisting of only 0s, because its not being set - is being signed and the order successfully executes, even though the action adds liquidity. That means that the deadline, liquidity to get, recipient of the funds, amount , etc. - basically all parameters that the user signs are independent from what is being sent on-chain.
To summarize, there are multiple occasions, where no nonce and actually no verification of execute params conformity to under signed order can be exploited:
Introduce nonce and verification that operator parameters are the same that the user signed.
3docSec (judge) commented:
namnm1991 (Krystal DeFi) acknowledged
